System and methods for accelerated data storage and retrieval

ABSTRACT

Systems and methods for providing accelerated data storage and retrieval utilizing lossless data compression and decompression. A data storage accelerator includes one or a plurality of high speed data compression encoders that are configured to simultaneously or sequentially losslessly compress data at a rate equivalent to or faster than the transmission rate of an input data stream. The compressed data is subsequently stored in a target memory or other storage device whose input data storage bandwidth is lower than the original input data stream bandwidth. Similarly, a data retrieval accelerator includes one or a plurality of high speed data decompression decoders that are configured to simultaneously or sequentially losslessly decompress data at a rate equivalent to or faster than the input data stream from the target memory or storage device. The decompressed data is then output at rate data that is greater than the output rate from the target memory or data storage device. The data storage and retrieval accelerator method and system may employed: in a disk storage adapter to reduce the time required to store and retrieve data from computer to disk; in conjunction with random access memory to reduce the time required to store and retrieve data from random access memory; in a display controller to reduce the time required to send display data to the display controller or processor; and/or in an input/output controller to reduce the time required to store, retrieve, or transmit data.

BACKGROUND

1. Technical Field

The present invention relates generally to data storage and retrievaland, more particularly to systems and methods for improving data storageand retrieval bandwidth utilizing lossless data compression anddecompression.

2. Description of the Related Art

Information may be represented in a variety of manners. Discreteinformation such as text and numbers are easily represented in digitaldata. This type of data representation is known as symbolic digitaldata. Symbolic digital data is thus an absolute representation of datasuch as a letter, figure, character, mark, machine code, or drawing.

Continuous information such as speech, music, audio, images and videofrequently exists in the natural world as analog information. As iswell-known to those skilled in the art, recent advances in very largescale integration (VLSI) digital computer technology have enabled bothdiscrete and analog information to be represented with digital data.Continuous information represented as digital data is often referred toas diffuse data. Diffuse digital data is thus a representation of datathat is of low information density and is typically not easilyrecognizable to humans in its native form.

There are many advantages associated with digital data representation.For instance, digital data is more readily processed, stored, andtransmitted due to its inherently high noise immunity. In addition, theinclusion of redundancy in digital data representation enables errordetection and/or correction. Error detection and/or correctioncapabilities are dependent upon the amount and type of data redundancy,available error detection and correction processing, and extent of datacorruption.

One outcome of digital data representation is the continuing need forincreased capacity in data processing, storage, and transmittal. This isespecially true for diffuse data where increases in fidelity andresolution create exponentially greater quantities of data. Datacompression is widely used to reduce the amount of data required toprocess, transmit, or store a given quantity of information. In general,there are two types of data compression techniques that may be utilizedeither separately or jointly to encode/decode data: lossy and losslessdata compression.

Lossy data compression techniques provide for an inexact representationof the original uncompressed data such that the decoded (orreconstructed) data differs from the original unencoded/uncompresseddata. Lossy data compression is also known as irreversible or noisycompression. Negentropy is defined as the quantity of information in agiven set of data. Thus, one obvious advantage of lossy data compressionis that the compression ratios can be larger than that dictated by thenegentropy limit, all at the expense of information content. Many lossydata compression techniques seek to exploit various traits within thehuman senses to eliminate otherwise imperceptible data. For example,lossy data compression of visual imagery might seek to deleteinformation content in excess of the display resolution or contrastratio of the target display device.

On the other hand, lossless data compression techniques provide an exactrepresentation of the original uncompressed data. Simply stated, thedecoded (or reconstructed) data is identical to the originalunencoded/uncompressed data. Lossless data compression is also known asreversible or noiseless compression. Thus, lossless data compressionhas, as its current limit, a minimum representation defined by thenegentropy of a given data set.

It is well known within the current art that data compression providesseveral unique benefits. First, data compression can reduce the time totransmit data by more efficiently utilizing low bandwidth data links.Second, data compression economizes on data storage and allows moreinformation to be stored for a fixed memory size by representinginformation more efficiently.

One problem with the current art is that existing memory storage devicesseverely limit the performance of consumer, entertainment, office,workstation, servers, and mainframe computers for all disk and memoryintensive operations. For example, magnetic disk mass storage devicescurrently employed in a variety of home, business, and scientificcomputing applications suffer from significant seek-time access delaysalong with profound read/write data rate limitations. Currently thefastest available (10,000) rpm disk drives support only a 17.1 Megabyteper second data rate (MB/sec). This is in stark contrast to the modernPersonal Computer's Peripheral Component Interconnect (PCI) Bus'sinput/output capability of 264 MB/sec and internal local bus capabilityof 800 MB/sec.

Another problem within the current art is that emergent high performancedisk interface standards such as the Small Computer Systems Interface(SCSI-3) and Fibre Channel offer only the promise of higher datatransfer rates through intermediate data buffering in random accessmemory. These interconnect strategies do not address the fundamentalproblem that all modern magnetic disk storage devices for the personalcomputer marketplace are still limited by the same physical mediarestriction of 17.1 MB/sec. Faster disk access data rates are onlyachieved by the high cost solution of simultaneously accessing multipledisk drives with a technique known within the art as data striping.

Additional problems with bandwidth limitations similarly occur withinthe art by all other forms of sequential, pseudo-random, and randomaccess mass storage devices. Typically mass storage devices includemagnetic and optical tape, magnetic and optical disks, and varioussolid-state mass storage devices. It should be noted that the presentinvention applies to all forms and manners of memory devices includingstorage devices utilizing magnetic, optical, and chemical techniques, orany combination thereof.

SUMMARY OF THE INVENTION

The present invention is directed to systems and methods for providingaccelerated data storage and retrieval by utilizing lossless datacompression and decompression. The present invention provides aneffective increase of the data storage and retrieval bandwidth of amemory storage device. In one aspect of the present invention, a methodfor providing accelerated data storage and retrieval comprises the stepsof:

-   -   receiving a data stream at an input data transmission rate which        is greater than a data storage rate of a target storage device;    -   compressing the data stream at a compression ratio which        provides a data compression rate that is greater than the data        storage rate;    -   storing the compressed data stream in the target storage device;    -   retrieving the compressed data stream from the target storage        device at a rate equal to a data access rate of the target        storage device; and    -   decompressing the compressed data at a decompression ratio to        provide an output data stream having an output transmission rate        which is greater than the data access rate of the target storage        device.

In another aspect of the present invention, the method for providingaccelerated data storage and retrieval utilizes a compression ratio thatis at least equal to the ratio of the input data transmission rate tothe data storage rate so as to provide continuous storage of the inputdata stream at the input data transmission rate.

In another aspect of the present invention, the method for providingaccelerated data storage and retrieval utilizes a decompression ratiowhich is equal to or greater than the ratio of the data access rate to amaximum accepted output data transmission rate so as to provide acontinuous and optimal data output transmission rate.

In another aspect of the present invention the data storage andretrieval accelerator method and system is employed in a disk storageadapter to reduce the time required to store and retrieve data fromcomputer to a disk memory device.

In another aspect of the present invention the data storage andretrieval accelerator method and system is employed in conjunction withrandom access memory to reduce the time required to store and retrievedata from random access memory.

In another aspect of the present invention a data storage and retrievalaccelerator method and system is employed in a video data storage systemto reduce the time required to store digital video data.

In another aspect of the present invention the data storage andretrieval accelerator method and system is employed in a displaycontroller to reduce the time required to send display data to thedisplay controller or processor.

In another aspect of the present invention the data storage andretrieval accelerator method and system is employed in an input/outputcontroller to reduce the time required to store, retrieve, or transmitdata various forms of data.

The present invention is realized due to recent improvements inprocessing speed, inclusive of dedicated analog and digital hardwarecircuits, central processing units, digital signal processors, dedicatedfinite state machines (and any hybrid combinations thereof), that,coupled with advanced data compression and decompression algorithms, areenabling of ultra high bandwidth data compression and decompressionmethods that enable improved data storage and retrieval bandwidth.

These and other aspects, features and advantages, of the presentinvention will become apparent from the following detailed descriptionof preferred embodiments, that is to be read in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a system for accelerated data storage andretrieval according to one embodiment of the present invention;

FIG. 2 is a flow diagram of a method for accelerated data storage inaccordance with one aspect of the present invention;

FIG. 3 is a flow diagram of a method for accelerated data retrieval inaccordance with one aspect of the present invention;

FIGS. 4 a and 4 b are timing diagrams of methods for accelerated datastorage according to the present invention;

FIGS. 5 a and 5 b are timing diagrams of methods for accelerated dataretrieval according to the present invention;

FIGS. 6 a and 6 b comprise a flow diagram of a method for accelerateddata storage in accordance with a further aspect of the presentinvention;

FIGS. 7 a and 7 b comprise a flow diagram of a method for accelerateddata retrieval in accordance with a further aspect of the presentinvention;

FIG. 8 is a detailed block diagram of a system for accelerated datastorage according to a preferred embodiment of the present invention;

FIG. 9 is a detailed block diagram of a system for accelerated dataretrieval according to a preferred embodiment of the present invention;

FIG. 10 is a block diagram of a system for accelerated video storageaccording to one embodiment of the present invention;

FIG. 11 is a block diagram of a system for accelerated retrieval ofvideo data according to one embodiment of the present invention;

FIG. 12 is a block diagram of an input/output controller system foraccelerated storage of analog, digital, and serial data according to oneembodiment of the present invention;

FIG. 13 is a flow diagram of a method for accelerated storage of analog,digital, and serial data according to one aspect of the presentinvention;

FIG. 14 is a block diagram of an input/output system for acceleratedretrieval of analog, digital, and serial data according to oneembodiment of the present invention; and

FIGS. 15 a and 15 b comprise a flow diagram of method for acceleratedretrieval of analog, digital, and serial data according to one aspect ofthe present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention is directed to systems and methods for providingimproved data storage and retrieval bandwidth utilizing lossless datacompression and decompression. In the following description, it is to beunderstood that system elements having equivalent or similarfunctionality are designated with the same reference numerals in theFigures. It is to be further understood that the present invention maybe implemented in various forms of hardware, software, firmware, or acombination thereof Preferably, the present invention is implemented ona computer platform including hardware such as one or more centralprocessing units (CPU) or digital signal processors (DSP), a randomaccess memory (RAM), and input/output (I/O) interface(s). The computerplatform may also include an operating system, microinstruction code,and dedicated processing hardware utilizing combinatorial logic orfinite state machines. The various processes and functions describedherein may be either part of the hardware, microinstruction code orapplication programs that are executed via the operating system, or anycombination thereof.

It is to be further understood that, because some of the constituentsystem components described herein are preferably implemented assoftware modules, the actual system connections shown in the Figures maydiffer depending upon the manner in that the systems are programmed. Itis to be appreciated that special purpose microprocessors, digitalsignal processors, dedicated hardware, or and combination thereof may beemployed to implement the present invention. Given the teachings herein,one of ordinary skill in the related art will be able to contemplatethese and similar implementations or configurations of the presentinvention.

Referring now to FIG. 1, a block diagram illustrates a system foraccelerated data storage and retrieval in accordance with an embodimentof the present invention. The system includes a data storage accelerator10, operatively coupled to a data storage device 45. The data storageaccelerator operates to increase the effective data storage rate of thedata storage device 45. It is to be appreciated that the data storagedevice 45 may be any form of memory device including all forms ofsequential, pseudo-random, and random access storage devices. The memorystorage device 45 may be volatile or non-volatile in nature, or anycombination thereof. Storage devices as known within the current artinclude all forms of random access memory, magnetic and optical tape,magnetic and optical disks, along with various other forms ofsolid-state mass storage devices. Thus it should be noted that thecurrent invention applies to all forms and manners of memory devicesincluding, but not limited to, storage devices utilizing magnetic,optical, and chemical techniques, or any combination thereof.

The data storage accelerator 10 receives and processes data blocks froman input data stream. The data blocks may range in size from individualbits through complete files or collections of multiple files, and thedata block size may be fixed or variable. In order to achieve continuousdata storage acceleration, the data storage accelerator 10 must beconfigured to compress a given input data block at a rate that is equalto or faster than receipt of the input data. Thus, to achieve optimumthroughput, the rate that data blocks from the input data stream may beaccepted by the data storage accelerator 10 is a function of the size ofeach input data block, the compression ratio achieved, and the bandwidthof the target storage device. For example, if the data storage device 45(e.g., a typical target mass storage device) is capable of storing 20megabytes per second and the data storage accelerator 10 is capable ofproviding an average compression ratio of 3:1, then 60 megabytes persecond may be accepted as input and the data storage acceleration isprecisely 3:1, equivalent to the average compression ratio.

It should be noted that it is not a requirement of the present inventionto configure the storage accelerator 10 to compress a given input datablock at a rate that is equal to or faster than receipt of the inputdata. Indeed, if the storage accelerator 10 compresses data at a ratethat is less than the input data rate, buffering may be applied toaccept data from the input data stream for subsequent compression.

Additionally, it is not a requirement that the data storage accelerator10 utilize data compression with a ratio that is at least the ratio ofthe input data stream to the data storage access rate of the datastorage device 45. Indeed, if the compression ratio is less than thisratio, the input data stream may be periodically halted to effectivelyreduce the rate of the input data stream. Alternatively, the input datastream or the output of the data accelerator 10 may be buffered totemporarily accommodate the mismatch in data bandwidth. An additionalalternative is to reduce the input data rate to rate that is equal to orslower than the ratio of the input data rate to the data storage deviceaccess rate by signaling the data input source and requesting a slowerdata input rate, if possible.

Referring again to FIG. 1, a data retrieval accelerator 80 isoperatively connected to and receives data from the data storage device45. The data retrieval accelerator 80 receives and processes compresseddata from data storage device 45 in data blocks that may range in sizefrom individual bits through complete files or collections of multiplefiles. Additionally, the input data block size may be fixed or variable.The data retrieval accelerator 80 is configured to decompress eachcompressed data block which is received from the data storage device 45.In order to achieve continuous accelerated data retrieval, the dataretrieval accelerator must decompress a given input data block at a ratethat is equal to or faster than receipt of the input data.

In a manner analogous to the data storage accelerator 10, achievingoptimum throughput with the data retrieval accelerator 80 is a functionof the rate that compressed data blocks are retrieved from the datastorage device 45, the size of each data block, the decompression ratioachieved, and the limitation on the bandwidth of the output data stream,if any. For example, if the data storage device 45 is capable ofcontinuously supplying 20 megabytes per second and the data retrievalaccelerator 80 is capable of providing an average decompression ratio of1:3, then a 60 megabytes per second output data stream is achieved, andthe corresponding data retrieval acceleration is precisely 1:3,equivalent to the average decompression ratio.

It is to be understood that it is not required that the data retrievalaccelerator 80 utilize data decompression with a ratio that is at mostequal to the ratio Of the retrieval rate of the data storage device 45to the maximum rate data output stream. Indeed, if the decompressionratio is greater than this ratio, retrieving data from the data storagedevice may be periodically halted to effectively reduce the rate of theoutput data stream to be at or below its maximum, Alternatively, thecompressed data retrieved from the data storage device 45 or the outputof the data decompressor may be buffered to temporarily accommodate themismatch in data bandwidth. An additional alternative is to increase theoutput data rate by signaling or otherwise requesting the data outputdevice(s) receiving the output data stream to accept a higher bandwidth,if possible.

Referring now to FIG. 2, a flow diagram of a method for accelerated datastorage according to one aspect of the present invention illustrates theoperation of the data storage acceleration shown in FIG. 1. Aspreviously stated above, data compression is performed on a per datablock basis. Accordingly, the initial input data block in the input datastream (step 200) is input into and compressed by the data storageaccelerator 10 (step 202). Upon completion of the encoding of the inputdata block, the encoded data block is then stored in the data storagedevice 45 (step 204). A check or other form of test is performed to seeif there are additional data blocks available in the input stream (step206). If no more data blocks are available, the storage accelerationprocess is terminated (step 208). If more data blocks are available inthe input data stream, the next data block is received (step 210) andthe process repeats beginning with data compression (step 202).

Referring now to FIG. 3, a flow diagram of a method for accelerated dataretrieval according to one aspect of the present invention illustratesthe operation of the data retrieval accelerator 80 shown in FIG. 1. Datadecompression is also performed on a per data block basis. The initialcompressed data block is retrieved from the storage device 45 (step 300)and is decompressed by the data retrieval accelerator 80 (step 302).Upon completion of the decoding of the initial data block, the decodeddata block is then output for subsequent processing, storage, ortransmittal (step 304). A check or other form of test is performed tosee if additional data blocks available from the data storage device(step 306). If no more data blocks are available, the data retrievalacceleration process is terminated (step 308). If more data blocks areavailable from the data storage device, the next data block is retrieved(step 310) and the process repeats beginning with data decompression(step 302).

Referring now to FIGS. 4 a and 4 b, a timing diagram illustrates methodsfor accelerated data storage utilizing data compression in accordancewith the present invention. Successive time intervals of equal durationare represented as T1 through T(n+2). Data block 1 is received from aninput stream of one or more data blocks. Similarly, data block 2 throughdata block n are received during time intervals T2 through Tn,respectively. For the purposes of discussion, FIGS. 4 a and 4 bdemonstrate one embodiment of the data storage utilizing a stream of ndata blocks. As previously stated, the input data stream is comprised ofone or more data blocks data blocks that may range in size fromindividual bits through complete files or collections of multiple files.Additionally, the input data block size may be fixed or variable.

In accordance with Method 1, compression of data block 1 and subsequentstorage of the encoded data block 1 occurs within time interval T1.Similarly, the compression and storage of each successive data blockoccurs within the time interval the data block is received.Specifically, data blocks 2 . . . n are compressed in time intervals T2. . . Tn, respectively, and the corresponding encoded data blocks 2 . .. n are stored during the time intervals T2 . . . Tn, respectively. Itis to be understood that Method 1 relies on data compression andencoding techniques that process data as a contiguous stream, i.e., arenot block oriented. It is well known within the current art that certaindata compression techniques including, but not limited to, dictionarycompression, run length encoding, null suppression and arithmeticcompression are capable of encoding data when received. Method 1possesses the advantage of introducing a minimum delay in the time fromreceipt of input to storage of encoded data blocks.

Referring again to FIGS. 4 a and 4 b, Method 2 illustrates compressingand storing data utilizing pipelined data processing. For Method 2,successive time intervals of equal duration are represented as T1through T(n+2). Data block 1 is received from an input stream of one ormore data blocks during time interval T1. Similarly, data block 2through data block n are received during time intervals T2 through Tn,respectively. Compression of data block 1 occurs during time interval T2and the storage of encoded data block 1 occurs during time interval T3.As shown by Method 2, compression of each successive data block occurswithin the next time interval after the data block is received and datastorage of the corresponding encoded data block occur in the next timeinterval after completion of data compression.

The pipelining of Method 2, as shown, utilizes successive single timeinterval delays for data compression and data storage. Within thecurrent invention, it is permissible to have increased pipelining tofacilitate additional data processing or storage delays. For example,data compression processing for a single input data block may utilizemore than one time interval. Accommodating more than one time intervalfor data compression requires additional data compressors to processsuccessive data blocks, eg., data compression processing of a singledata block through three successive time intervals requires three datacompressors, each processing a successive input data block. Due to theprinciple of causality, encoded data blocks are output only aftercompression encoding.

Method 2 provides for block oriented processing of the input datablocks. Within the current art, block oriented data compressiontechniques provide the opportunity for increased data compressionratios. The disadvantage of Method 2 is increased delay from receipt ofinput data block to storage of encoded data. Depending on factors suchas the size of input data blocks, the rate that they are received, thetime required for data compression processing, the data compressionratio achieved, the bandwidth of the data storage device, and theintended application, the delay may or may not be significant. Forexample, in a modern database system, recording data for archivalpurposes, the opportunity for increased data compression may faroutweigh the need for minimum delay. Conversely, in systems such as amilitary real-time video targeting system, minimizing delay is often ofthe essence. It should be noted that Method 1 and Method 2 are notmutually exclusive, and may be utilized in any combination.

Referring now to FIGS. 5 a and 5 b, a timing diagram illustrates methodsfor accelerated data retrieval utilizing data decompression inaccordance the present invention shown. Successive time intervals ofequal duration are represented as T1 through T(n+2). Data block 1 isretrieved or otherwise accepted as input from one or more compresseddata blocks retrieved from a data storage device. As shown, data block 2through data block n are retrieved during time intervals T2 through Tn,respectively. For the purposes of discussion, FIGS. 5 a and 5 bdemonstrate one embodiment of the data retrieval accelerator utilizing astream of n data blocks. Once again, the retrieved data stream iscomprised of one or more data blocks that may range in size fromindividual bits through complete files or collections of multiple files.Additionally, the retrieved data block size may be fixed or variable.

In accordance with Method 1, decompression of data block 1 andsubsequent outputting of the decoded data block 1 occurs within timeinterval T1. Similarly, decompression and outputting of each successivedata block occurs within the time intervals they are retrieved. Inparticular, data block 2 through data block n are decompressed anddecoded data block 2 through decoded data block n are output during timeintervals T2 . . . Tn, respectively. It is to be understood that Method1 relies on data decompression and decoding techniques that processcompressed data as a contiguous stream, i.e., are not block oriented. Itis well known within the current art that certain data decompressiontechniques including, but not limited to , dictionary compression, runlength encoding, null suppression and arithmetic compression are capableof decoding data when received. Method 1 possesses the advantage ofintroducing a minimum delay in the time from retrieval of compresseddata to output of decoded data blocks.

Referring again to FIGS. 5 a and 5 b, Method 2 involves decompressingand outputting data utilizing pipelined data processing. For Method 2,successive time intervals of equal duration are represented as T1through T(n+2). Data block 1 through data block n are retrieved orotherwise accepted as input from a data storage device during timeintervals T1 through Tn, respectively. Decompression of data block 1occurs during time interval T2 and the decoded data block 1 is outputduring time interval T3. Similarly, decompression of each successivedata block occurs within the next time interval after the data block isretrieved and the outputting of the decoded data block occurs during thenext time interval after completion of data decompression.

The pipelining of Method 2, utilizes successive single time intervaldelays for data decompression and data output. Within the currentinvention, it is permissible to have increased pipelining to facilitateadditional data retrieval or data decompression processing delays. Forexample, data decompression processing for a single input data block mayutilize more than one time interval. Accommodating more than one timeinterval for data compression requires additional data decompressors toprocess successive compressed data blocks, e.g., data decompressionprocessing of a single data block through three successive timeintervals requires three data decompressors, each processing asuccessive input data block. Due to the principle of causality, decodeddata blocks are only output after decompression decoding.

As before, Method 2 provides for block oriented processing of theretrieved data blocks. Within the current art, block oriented datadecompression techniques provide the opportunity to utilize datacompression encoders that increase data compression ratios. Thedisadvantage of method 2 is increased delay from retrieval of compresseddata block to output of decompressed data. As previously discussed fordata storage acceleration, depending on the size of retrieved datablocks, the rate that they are retrieved, the time required for datadecompression processing, the data decompression ratio achieved, thebandwidth of the data output, and the intended application, the delaymay or may not be significant.

Referring now to FIGS. 6 a and 6 b, a flow diagram illustrates a methodfor accelerated data storage according to a further aspect of thepresent invention. With this method, the data compression rate of thestorage accelerator 10 is not required to be equal to or greater thanthe ratio of the input data rate to the data storage access rate. Aspreviously stated above, data compression is performed on a per datablock basis. Accordingly, the initial input data block in the input datastream is received (step 600) and then timed and counted (step 602).Timing and counting enables determination of the bandwidth of the inputdata stream. The input data block is then buffered (step 604) andcompressed by the data storage accelerator 10 (step 606). During andafter the encoding of the input data block, the encoded data block isthen timed and counted (step 608), thus enabling determination of thecompression ratio and compression bandwidth. The compressed, timed andcounted data block is then buffered (step 610). The compression ratioand bandwidths of the input data stream and the encoder are thendetermined (step 612). The compressed data block is then stored in thedata storage device 45 (step 614). Checks or other forms of testing areapplied to ensure that the data bandwidths of the input data stream,data compressor, and data storage device are compatible (step 616). Ifthe bandwidths are not compatible, then one or more system parametersmay be modified to make the bandwidths compatible (step 618). Forinstance, the input bandwidth may be adjusted by either not acceptinginput data requests, lowering the duty cycle of input data requests, orby signaling one or more of the data sources that transmit the inputdata stream to request or mandate a lower data rate. In addition, thedata compression ratio of the data storage accelerator 10 may beadjusted by applying a different type of encoding process such asemploying a single encoder, multiple parallel or sequential encoders, orany combination thereof. Furthermore, additional temporary buffering ofeither the input data stream or the compressed data stream (or both) maybe utilized.

By way of example, assuming the input data rate is 90 MB/sec and thedata storage accelerator 10 provides a compression ration of 3:1, thenthe output of the data storage accelerator 10 would be 30 MB/sec. If themaximum data storage rate of the data storage device 45 is 20 MB/sec(which is less than the data rate output from the data storageaccelerator 10), data congestion and backup would occur at the output ofthe data storage accelerator 10. This problem may be solved by adjustingany one of the system parameters as discussed above, e.g., by adjustingthe compression ratio to provide a data output rate from the datastorage accelerator 10 to be equal to the data storage rate of the datastorage device 45.

On the other hand, if the bandwidths are compatible (or made compatibleby adjusting one or more of the system parameters), then a check orother form of test is performed to determine if there are additionaldata blocks available in the input stream (step 620). If no more datablocks are available, the storage acceleration process is terminated(step 622). If more data blocks are available in the input data stream,the next data block is received (step 624) and the process repeatsbeginning with timing and counting of the input data block (step 602).

Referring now to FIGS. 7 a and 7 b, a flow diagram illustrates a methodfor accelerated data retrieval according to one aspect of the presentinvention. With this method, the data decompression ratio is notrequired to be less than or equal to the ratio of the data retrievalaccess rate to the maximum output data rate. As previously stated above,data decompression is performed on a per data block basis. Accordingly,the initial input data block is retrieved from the storage device (step700) and is timed and counted (step 702). Timing and counting enablesdetermination of the bandwidth of data retrieval. The retrieved datablock is then buffered (step 704) and decompressed by the data retrievalaccelerator 80 (step 706). During and after the decoding of the inputdata block, the decoded data block is then timed and counted (step 708),thus enabling determination of the decompression ratio and decompressionbandwidth. The decompressed, timed and counted data block is thenbuffered (step 710). The decompression ratio and bandwidths of theretrieved data and the decoder are then determined (step 712). Thedecompressed data block is then output (step 714). Checks or other formsof testing are applied to ensure that the data bandwidths of theretrieved data, data decompressor, and data output are compatible (step716). If the bandwidths are not compatible, then one or more systemparameters may be modified to make the bandwidths compatible (step 718).For instance, the data retrieval bandwidth may be adjusted either notaccepting (continuously) data blocks retrieved from the data storagedevice or lowering the duty cycle of data blocks retrieved from the datastorage device. In addition, one or more of the output data devices thatreceive the output data stream may be signaled or otherwise requested toaccept a higher data rate. Moreover, a different type of decodingprocess may be applied to adjust the data decompression rate byapplying, for example, a single decoder, multiple parallel or sequentialdecoders, or any combination thereof. Also, additional temporarybuffering of either the retrieved or output data or both may beutilized.

By way of example, assuming the data storage device 45 has a dataretrieval rate of 20 MB/sec and the data retrieval accelerator 80provides a 1:4 decompression ratio, then the output of the dataretrieval accelerator 80 would be 80 MB/sec. If the maximum output datatransmission rate that can be accepted from the data retrievalaccelerator 80 is 60 MB/sec (which is lower than the data output datarate of 80 MB/sec of the data retrieval accelerator 80), data congestionand backup would occur at the output of the data retrieval accelerator80. This problem may be solved by adjusting any one of the systemparameters as discussed above, e.g., by adjusting the decompressionratio to provide a data output rate from the data storage accelerator 80to be equal to the maximum accepted output data transmission rate.

On the other hand, if the bandwidths are compatible (or made compatibleby adjusting one or more system parameters), then a check or other formof test is performed to see if there are additional data blocksavailable from the data storage device (step 720). If no more datablocks are available for output, the retrieval acceleration process isterminated (step 722). If more data blocks are available to be retrievedfrom the data storage device, the next data block is retrieved (step724) and the process repeats beginning with timing and counting of theretrieved data block (return to step 702).

It is to be understood that any conventional compression/decompressionsystem and method (which comply with the above mentioned constraints)may be employed in the data storage accelerator 10 and data retrievalaccelerator 80 for providing accelerated data storage and retrieval inaccordance with the present invention. Preferably, the present inventionemploys the data compression/decompression techniques disclosed in U.S.Ser. No. 09/210,491 entitled “Content Independent Data CompressionMethod and System,” filed on Dec. 11, 1998, which is commonly assignedand which is fully incorporated herein by reference. It is to beappreciated that the compression and decompression systems and methodsdisclosed in U.S. Ser. No. 09/210,491 are suitable for compressing anddecompressing data at rates which provide accelerated data storage andretrieval.

Referring now to FIG. 8, a detailed block diagram illustrates apreferred system for accelerated data storage which employs acompression system as disclosed in the above-incorporated U.S. Ser. No.09/210,491. In this embodiment, the data storage accelerator 10 acceptsdata blocks from an input data stream and stores the input data block inan input buffer or cache 15. It is to be understood that the systemprocesses the input data stream in data blocks that may range in sizefrom individual bits through complete files or collections of multiplefiles. Additionally, the input data block size may be fixed or variable.A counter 20 counts or otherwise enumerates the size of input data blockin any convenient units including bits, bytes, words, double words. Itshould be noted that the input buffer 15 and counter 20 are not requiredelements of the present invention. The input data buffer 15 may beprovided for buffering the input data stream in order to output anuncompressed data stream in the event that, as discussed in furtherdetail below, every encoder fails to achieve a level of compression thatexceeds an a priori specified minimum compression ratio threshold.

Data compression is performed by an encoder module 25 which may comprisea set of encoders E1, E2, E3 . . . En. The encoder set E1, E2, E3 . . .En may include any number “n” (where n may=1) of those lossless encodingtechniques currently well known within the art such as run length,Huffman, Lempel-Ziv Dictionary Compression, arithmetic coding, datacompaction, and data null suppression. It is to be understood that theencoding techniques are selected based upon their ability to effectivelyencode different types of input data. It is to be appreciated that afull complement of encoders are preferably selected to provide a broadcoverage of existing and future data types.

The encoder module 25 successively receives as input each of thebuffered input data blocks (or unbuffered input data blocks from thecounter module 20). Data compression is performed by the encoder module25 wherein each of the encoders E1 . . . En processes a given input datablock and outputs a corresponding set of encoded data blocks. It is tobe appreciated that the system affords a user the option toenable/disable any one or more of the encoders E1 . . . En prior tooperation. As is understood by those skilled in the art, such featureallows the user to tailor the operation of the data compression systemfor specific applications. It is to be further appreciated that theencoding process may be performed either in parallel or sequentially. Inparticular, the encoders E1 through En of encoder module 25 may operatein parallel (i.e., simultaneously processing a given input data block byutilizing task multiplexing on a single central processor, via dedicatedhardware, by executing on a plurality of processor or dedicated hardwaresystems, or any combination thereof). In addition, encoders E1 throughEn may operate sequentially on a given unbuffered or buffered input datablock. This process is intended to eliminate the complexity andadditional processing overhead associated with multiplexing concurrentencoding techniques on a single central processor and/or dedicatedhardware, set of central processors and/or dedicated hardware, or anyachievable combination. It is to be further appreciated that encoders ofthe identical type may be applied in parallel to enhance encoding speed.For instance, encoder E1 may comprise two parallel Huffman encoders forparallel processing of an input data block.

A buffer/counter module 30 is operatively connected to the encodermodule 25 for buffering and counting the size of each of the encodeddata blocks output from encoder module 25. Specifically, thebuffer/counter 30 comprises a plurality of buffer/counters BC1, BC2, BC3. . . BCn, each operatively associated with a corresponding one of theencoders E1 . . . En. A compression ratio module 35, operativelyconnected to the output buffer/counter 30, determines the compressionratio obtained for each of the enabled encoders E1 . . . En by takingthe ratio of the size of the input data block to the size of the outputdata block stored in the corresponding buffer/counters BC1 . . . BCn. Inaddition, the compression ratio module 35 compares each compressionratio with an a priori-specified compression ratio threshold limit todetermine if at least one of the encoded data blocks output from theenabled encoders E1 . . . En achieves a compression that exceeds an apriori-specified threshold. As is understood by those skilled in theart, the threshold limit may be specified as any value inclusive of dataexpansion, no data compression or expansion, or any arbitrarily desiredcompression limit. A description module 38, operatively coupled to thecompression ratio module 35, appends a corresponding compression typedescriptor to each encoded data block which is selected for output so asto indicate the type of compression format of the encoded data block. Adata compression type descriptor is defined as any recognizable datatoken or descriptor that indicates which data encoding technique hasbeen applied to the data. It is to be understood that, since encoders ofthe identical type may be applied in parallel to enhance encoding speed(as discussed above), the data compression type descriptor identifiesthe corresponding encoding technique applied to the encoded data block,not necessarily the specific encoder. The encoded data block having thegreatest compression ratio along with its corresponding data compressiontype descriptor is then output for subsequent data processing, storage,or transmittal. If there are no encoded data blocks having a compressionratio that exceeds the compression ratio threshold limit, then theoriginal unencoded input data block is selected for output and a nulldata compression type descriptor is appended thereto. A null datacompression type descriptor is defined as any recognizable data token ordescriptor that indicates no data encoding has been applied to the inputdata block. Accordingly, the unencoded input data block with itscorresponding null data compression type descriptor is then output forsubsequent data processing, storage, or transmittal.

The data storage acceleration device 10 is connected to a data storagedevice interface 40. The function of the data storage interface 40 is tofacilitate the formatting and transfer of data to one or more datastorage devices 45. The data storage interface may be any of the datainterfaces known to those skilled in the art such as SCSI (SmallComputer Systems Interface), Fibre Channel, “Firewire”, IEEE P1394, SSA(Serial Storage Architecture), IDE (Integrated Disk Electronics), andATA/ATAPI interfaces. It should be noted that the storage device datainterface 40 is not required for implementing the present invention. Asbefore, the data storage device 45 may be any form of memory deviceincluding all forms of sequential, pseudo-random, and random accessstorage devices. The data storage device 45 may be volatile ornon-volatile in nature, or any combination thereof. Storage devices asknown within the current art include all forms of random access memory(RAM), magnetic and optical tape, magnetic and optical disks, along withvarious other forms of solid-state mass storage devices (e.g., ATA/ATAPIIDE disk). Thus it should be noted that the current invention applies toall forms and manners of memory devices including, but not limited to,storage devices utilizing magnetic, optical, and chemical techniques, orany combination thereof.

Again, it is to be understood that the embodiment of the data storageaccelerator 10 of FIG. 8 is exemplary of a preferred compression systemwhich may be implemented in the present invention, and that othercompression systems and methods known to those skilled in the art may beemployed for providing accelerated data storage in accordance with theteachings herein. Indeed, in another embodiment of the compressionsystem disclosed in the above-incorporated U.S. Ser. No. 09/210,491, atimer is included to measure the time elapsed during the encodingprocess against an a priori-specified time limit. When the time limitexpires, only the data output from those encoders (in the encoder module25) that have completed the present encoding cycle are compared todetermine the encoded data with the highest compression ratio. The timelimit ensures that the real-time or pseudo real-time nature of the dataencoding is preserved. In addition, the results from each encoder in theencoder module 25 may be buffered to allow additional encoders to besequentially applied to the output of the previous encoder, yielding amore optimal lossless data compression ratio. Such techniques arediscussed in greater detail in the above-incorporated U.S. Ser. No.09/210,491.

Referring now to FIG. 9, a detailed block diagram illustrates apreferred system for accelerated data retrieval employing adecompression system as disclosed in the above-incorporated U.S. Ser.No. 09/210,491. In this embodiment, the data retrieval accelerator 80retrieves or otherwise accepts data blocks from one or more data storagedevices 45 and inputs the data via a data storage interface 50. It is tobe understood that the system processes the input data stream in datablocks that may range in size from individual bits through completefiles or collections of multiple files. Additionally, the input datablock size may be fixed or variable. As stated above, the memory storagedevice 45 may be volatile or non-volatile in nature, or any combinationthereof. Storage devices as known within the current art include allforms of random access memory, magnetic and optical tape, magnetic andoptical disks, along with various other forms of solid-state massstorage devices. Thus it should be noted that the current inventionapplies to all forms and manners of memory devices including storagedevices utilizing magnetic, optical, and chemical techniques, or anycombination thereof. The data storage device interface 50 converts theinput data from the storage device format to a format useful for datadecompression.

The storage device data interface 50 is operatively connected to thedata retrieval accelerator 80 which is utilized for decoding the stored(compressed) data, thus providing accelerated retrieval of stored data.In this embodiment, the data retrieval accelerator 80 comprises an inputbuffer 55 which receives as input an uncompressed or compressed datastream comprising one or more data blocks. The data blocks may range insize from individual bits through complete files or collections ofmultiple files. Additionally, the data block size may be fixed orvariable. The input data buffer 55 is preferably included (not required)to provide storage of input data for various hardware implementations. Adescriptor extraction module 60 receives the buffered (or unbuffered)input data block and then parses, lexically, syntactically, or otherwiseanalyzes the input data block using methods known by those skilled inthe art to extract the data compression type descriptor associated withthe data block. The data compression type descriptor may possess valuescorresponding to null (no encoding applied), a single applied encodingtechnique, or multiple encoding techniques applied in a specific orrandom order (in accordance with the data compression system embodimentsand methods discussed above).

A decoder module 65 includes one or more decoders D1 . . . Dn fordecoding the input data block using a decoder, set of decoders, or asequential set of decoders corresponding to the extracted compressiontype descriptor. The decoders D1 . . . Dn may include those losslessencoding techniques currently well known within the art, including: runlength, Huffman, Lempel-Ziv Dictionary Compression, arithmetic coding,data compaction, and data null suppression. Decoding techniques areselected based upon their ability to effectively decode the variousdifferent types of encoded input data generated by the data compressionsystems described above or originating from any other desired source.

As with the data compression systems discussed in U.S. application Ser.No. 09/210,491, the decoder module 65 may include multiple decoders ofthe same type applied in parallel so as to reduce the data decodingtime. The data retrieval accelerator 80 also includes an output databuffer or cache 70 for buffering the decoded data block output from thedecoder module 65. The output buffer 70 then provides data to the outputdata stream. It is to be appreciated by those skilled in the art thatthe data retrieval accelerator 80 may also include an input data counterand output data counter operatively coupled to the input and output,respectively, of the decoder module 65. In this manner, the compressedand corresponding decompressed data block may be counted to ensure thatsufficient decompression is obtained for the input data block.

Again, it is to be understood that the embodiment of the data retrievalaccelerator 80 of FIG. 9 is exemplary of a preferred decompressionsystem and method which may be implemented in the present invention, andthat other data decompression systems and methods known to those skilledin the art may be employed for providing accelerated data retrieval inaccordance with the teachings herein.

In accordance with another aspect of the present invention, the datastorage and retrieval accelerator system and method may be employed infor increasing the storage rate of video data. In particular, referringnow to FIG. 10, a block diagram illustrates a system for providingaccelerated video data storage in accordance with one embodiment of thepresent invention. The video data storage acceleration system accepts asinput one or more video data streams that are analog, digital, or anycombination thereof in nature. The input multiplexer 1010 selects theinitial video data stream for data compression and acceleration. Theinput multiplexer 1010 is operatively connected to an analog to digitalconverter 1020 which converts analog video inputs to digital format ofdesired resolution. The analog to digital converter 1020 may alsoinclude functions to strip video data synchronization to perform otherdata formatting functions. It should be noted that the analog to digitalconversion process is not required for digital video inputs. The analogto digital converter 1020 is operatively connected a video memory 1030that is, in turn, operatively connected to a video processor 1040. Thevideo processor 1040 performs manipulation of the digital video data inaccordance with any user desired processing functions. The videoprocessor 1040 is operatively coupled to a video output memory 1050,that is operatively connected to a data storage accelerator 10 whichcompresses the video data to provide accelerated video data to theoutput data stream for subsequent data processing, storage, ortransmittal of the video data. This video data acceleration process isrepeated for all data blocks in the input data stream. If more videodata blocks are available in the input data stream, the videomultiplexer selects the next block of video for accelerated processing.Again, it is to be understood that the data storage accelerator 10 mayemploy any compression system which is capable of compressing data at arate suitable for providing accelerated video data storage in accordancewith the teachings herein.

In accordance with another aspect of the present invention, theaccelerated data storage and retrieval system may be employed in adisplay controller to reduce the time required to send display data to adisplay controller or processor. In particular, referring now to FIG.11, a block diagram illustrates a display accelerator system inaccordance with one embodiment of the present invention. The videodisplay accelerator accepts as input one or more digital display datablocks from an input display data stream. It is to be understood thatthe system processes the input data stream in data blocks that may rangein size from individual bits through complete files or collections ofmultiple files. Additionally, the input video data block size may befixed or variable. The input data blocks are processed by a dataretrieval accelerator 80 which employs a data decompression system inaccordance with the teachings herein. Upon completion of datadecompression, the decompressed data block is then output to a displaymemory 1110 that provides data to a display processor 1120. The displayprocessor 1120 performs any user desired processing function. It is wellknown within the current art that display data is often provided in oneor more symbolic formats such as Open Graphics Language (Open GL) oranother display or image language. The display processor 1120 isoperatively connected an output memory buffer 1130. The output memory1130 supplies data to a display formatter 1140 that converts the data toa format compatible with the output display device or devices. Data fromthe display formatter 1140 is provided to the display driver 1150 thatoutputs data in appropriate format and drive signal levels to one ormore display devices. It should be noted that the display memory 1110,display processor 1120, output memory 1130, display formatter 1140, anddisplay driver 1150 are not required elements of the present invention.

In accordance with yet another aspect of the present invention, the datastorage and retrieval accelerator system and method may be employed inan I/O controller to reduce the time for storing, retrieving ortransmitting parallel data streams. In particular, referring now to FIG.12, a block diagram illustrates a system for accelerated data storage ofanalog, digital, and serial data in accordance with one embodiment ofthe present invention. The data storage accelerator 10 is capable ofaccepting one or more simultaneous analog, parallel digital, and serialdata inputs. An analog input multiplexer 1205 selects the initial analogdata for data compression and acceleration. The analog input multiplexer1205 is operatively connected to an analog to digital converter 1210that converts the analog input signal to digital data of the desiredresolution. The digitized data output of the analog to digital converter1210 is stored in an analog data memory buffer 1215 for subsequent datastorage acceleration. Similarly, a parallel digital data inputmultiplexer 1220 selects the initial parallel digital data for datacompression and acceleration. The parallel digital data inputmultiplexer 1220 is operatively connected to an input data latch 1225that holds the input parallel digital data. The parallel digital data isthen stored in digital data memory buffer 1245 for subsequent datastorage acceleration. In addition, a serial digital data inputmultiplexer 1235 selects the initial serial digital data for datacompression and acceleration. The serial digital data input multiplexer1235 is operatively connected to a serial data interface 1240 thatconverts the serial data stream to a format useful for dataacceleration. The formatted serial digital data is then stored in serialdata memory buffer 1245 for subsequent data acceleration. The analogdata memory 1215, parallel digital data memory 1230, and serial datamemory 1245 are operatively connected to the data storage acceleratordevice 10. Data is selected from each data memory subsystem based upon auser defined algorithm or other selection criteria. It should be notedthat the analog input multiplexer 1205, analog to digital converter1210, analog data memory 1215, parallel data input multiplexer 1220,data latch 1225, digital data memory 1230, serial data input multiplexer1235, serial data interface 1240, serial data memory 1245, and counter20 are not required elements of the present invention. As stated above,the data storage accelerator 10 employs any of the data compressionmethods disclosed in the above-incorporated U.S. Ser. No. 09/1210,491,or any conventional data compression method suitable for compressingdata at a rate necessary for obtaining accelerated data storage. Thedata storage accelerator supplies accelerated data to the output datastream for subsequent data processing, storage, or transmittal.

Referring now to FIG. 13, a flow diagram illustrates a method foraccelerated data storage of analog, digital, and serial data accordingto one aspect of the present invention. The analog input multiplexerselects the initial analog data for data compression and acceleration(step 1300). The analog input multiplexer provides analog data to theanalog to digital converter that converts the analog input signal todigital data of the desired resolution (step 1302). The digitized dataoutput of the analog to digital converter is then buffered in the analogdata memory buffer (step 1304) for subsequent data acceleration.Similarly, the parallel digital data multiplexer selects the initialparallel digital data for data compression and acceleration (step 1306).The parallel digital data multiplexer provides data to the input datalatch that then holds the input parallel digital data (step 1308). Theparallel digital data is then stored in digital data memory buffer forsubsequent data acceleration (step 1310). The serial digital data inputmultiplexer selects the initial serial digital data for data compressionand acceleration (step 1312). The serial digital data input multiplexerprovides serial data to the serial data interface that converts theserial data stream to a format useful for data acceleration (step 1314).The formatted serial digital data is then stored in the serial datamemory buffer for subsequent data acceleration (step 1316). A test orother check is performed to see if new analog data is available (step1318). If no new analog data is available a second check is performed tosee if new parallel data is available (step 1320). If no new paralleldata is available, a third test is performed to see if new serial datais available (step 1322). If no new serial data is available (step 1322)the test sequence repeats with the test for new analog data (step 1318).If new analog data block is available (step 1318), or if new paralleldata block is available (step 1320), or if new serial data block isavailable (step 1322), the input data block is compressed by the datastorage accelerator (step 1324) utilizing any compression methodsuitable for providing accelerated data storage in accordance with theteachings herein. After data compression is complete, the compresseddata block is then output subsequent accelerated data processing,storage, or transmittal (step 1326). After outputting data the processrepeats beginning with a test for new analog data (return to step 1318).

Referring now to FIG. 14, a block diagram illustrates a system foraccelerated retrieval of analog, digital, and serial data in accordancewith one embodiment of the present invention. A data retrievalaccelerator 80 receives data from an input data stream. It is to beunderstood that the system processes the input data stream in datablocks that may range in size from individual bits through completefiles or collections of multiple files. Additionally, the input datablock size may be fixed or variable. The data retrieval accelerator 80decompresses the input data utilizing any of the decompression methodssuitable for providing accelerated data retrieval in accordance with theteachings herein. The data retrieval accelerator 80 is operativelyconnected to analog data memory 1405, digital data memory 1420, andserial data memory 1435. Dependent upon the type of input data block,the decoded data block is stored in the appropriate analog 1405, digital1420, or serial 1435 data memory.

The analog data memory 1405 is operatively connected to a digital toanalog converter 1410 that converts the decompressed digital data blockinto an analog signal. The digital to analog converter 1410 is furtheroperatively connected to an analog hold and output driver 1415. Theanalog hold and output driver 1415 demultiplexes the analog signaloutput from the digital to analog converter 1410, samples and holds theanalog data, and buffers the output analog data.

In a similar manner, the digital data memory 1420 is operativelyconnected to a digital data demultiplexer 1425 that routes thedecompressed parallel digital data to the output data latch and driver1430. The output latch and driver 1430 holds the digital data andbuffers the parallel digital output.

Likewise, the serial data memory 143 5 is operatively connected to aserial data interface 1440 that converts the decompressed data block toan output serial data stream. The serial data interface 1440 is furtheroperatively connected to the serial demultiplexer and driver 1445 thatroutes the serial digital data to the appropriate output and buffers theserial data output.

Referring now to FIGS. 15 a and 15 b, a flow diagram illustrates amethod for accelerated retrieval of analog, digital, and serial dataaccording to one aspect of the present invention. An initial data blockis received (step 1500) and then decompressed by the data storageretrieval accelerator (step 1502). Upon completion of datadecompression, a test or other check is performed to see if the datablock is digitized analog data (step 1508). If the data block is notdigitized analog data, a second check is performed to see if the datablock is parallel digital data (step 1510). If the data block is notparallel digital data, a third test is performed to see if the datablock serial data (step 1512). The result of at least one of the threetests will be affirmative.

If the data block is comprised of digitized analog data, the decodeddata block is buffered in an “analog” digital data memory (step 1514).The decoded data block is then converted to an analog signal by adigital to analog converter (step 1520). The analog signal is thenoutput (step 1522).

If the data block is comprised of parallel digital data, the decodeddata block is buffered in a “parallel” digital data memory (step 1516).The decoded data block is then demultiplexed (step 1524) and routed tothe appropriate the output data latch and driver. The output latch anddriver then holds the digital data and buffers the parallel digitaloutput (step 1526).

If the data block is comprised of serial data, the decoded data block isbuffered in “serial” digital data memory (step 1518). The decoded datais then formatted to a serial data format (step 1528). The serial datais then demultiplexed, routed to the appropriate output, and output to abuffer (step 1530).

Upon output of analog data (step 1522), parallel digital data (step1526), or serial digital data (step 1530), a test or other form of checkis performed for more data blocks in the input stream (step 1532). If nomore data blocks are available, the test repeats (return to step 1532).If a data block is available, the next data block is received (step1534) and the process repeats beginning with step 1502.

Although illustrative embodiments have been described herein withreference to the accompanying drawings, it is to be understood that thepresent invention is not limited to those precise embodiments, and thatvarious other changes and modifications may be affected therein by oneskilled in the art without departing from the scope or spirit of theinvention. All such changes and modifications are intended to beincluded within the scope of the invention as defined by the appendedclaims.

1-47. (canceled)
 48. A system comprising: a memory device; and a dataaccelerator, wherein said data accelerator is coupled to said memorydevice, a data stream is received by said data accelerator in receivedform, said data stream includes a first data block and a second datablock, said data stream is compressed by said data accelerator toprovide a compressed data stream by compressing said first data blockwith a first compression technique and said second data block with asecond compression technique, said first and second compressiontechniques are different, said compressed data stream is stored on saidmemory device, said compression and storage occurs faster than said datastream is able to be stored on said memory device in said received form,a first data descriptor is stored on said memory device indicative ofsaid first compression technique, and said first descriptor is utilizedto decompress the portion of said compressed data stream associated withsaid first data block.
 49. The system of claim 48, wherein said dataaccelerator stores said first descriptor to said memory device.
 50. Thesystem of claim 48, wherein said data accelerator retrieves said firstdescriptor and said compressed data stream from said memory device. 51.The system of claim 48, wherein said data accelerator retrieves saidcompressed data stream from said memory device.
 52. The system of claim48, wherein said data accelerator retrieves said compressed data streamfrom said memory device and said decompression of the portion of saidcompressed data stream associated with said first data block isperformed by said data accelerator.
 53. The system of claim 48, whereinsaid data accelerator is coupled to said memory device via a smallcomputer systems interface.
 54. The system of claim 48, wherein saiddata accelerator is coupled to said memory device via a fibre channel.55. The system of claim 48, wherein said data accelerator is coupled tosaid memory device via a serial storage architecture.
 56. The system ofclaim 48, wherein said memory device is a magnetic memory device. 57.The system of claim 48, wherein said memory device is an optical memorydevice.
 58. The system of claim 48, wherein said memory device is arandom access memory.
 59. The system of claim 48, wherein said memorydevice is a solid-state mass storage device.
 60. The system of claim 48,wherein said first compression technique includes compressing withHuffman encoding.
 61. The system of claim 48, wherein said firstcompression technique includes compressing with Lempel-Ziv encoding. 62.The system of claim 48, wherein said first compression techniqueincludes compressing with a plurality of encoders in a serialconfiguration.
 63. The system of claim 48, wherein said firstcompression technique includes compressing with a plurality of encodersin a parallel configuration.
 64. The system of claim 48, wherein saidfirst compression technique includes compressing with a plurality ofencoders in a parallel configuration and each one of said plurality ofencoders is an identical type of encoder.
 65. The system of claim 48,wherein said first compression technique comprises compressing with afirst encoder.
 66. The system of claim 48, wherein said data streamcomprises a collection of multiple files.
 67. The system of claim 48,wherein said data stream includes a third data block and a fourth datablock.
 68. The system of claim 48, wherein said data stream includes athird data block and a fourth data block and said compressed data streamis provided by compressing said third data block with a thirdcompression technique and compressing said fourth data block with afourth compression technique.
 69. The system of claim 48, wherein saiddata stream is an analog video data stream.
 70. The system of claim 48,wherein said data stream is a digital video data stream.